The present invention generally relates to a storage apparatus, and in particular relates to a disk array device that uses inexpensive disks.
In recent years, so-called disk array devices in which a plurality of hard disk devices are managed and operated in RAID (Redundant Array of Inexpensive Disks) format are being widely used as the storage apparatus for storing data in corporations and government offices.
Prices of disk array devices have been lowered in recent years, and inexpensive SATA (Serial AT Attachment) disks are being used instead of fibre channel disks as the hard disk device pursuant to such price reduction.
Although SATA disks are inexpensive, they are also unreliable. Thus, for instance, if a hard disk drive storing information in which the reliability heeds to be ensured such as system information required for operating the disk array device is simply replaced from A fibre channel disk to a SATA disk, the reliability of the overall disk array device will deteriorate.
In light of the above, Japanese Patent Laid-Open Publication No. 2006-72435 (Patent Document 1) proposes a method of determining whether write data has been normally stored in a storage unit. Specifically, this method includes the steps of commanding a storage unit to store, in response to a request from a host, a first check code based on write data in a cache memory, write the write data attached to the first check code in a prescribed storage area, and read the data stored in the prescribed storage area A second check code is created based on the read data and, if the correspondence relationship of the first and second check codes is correct, it is determined that the write data has been normally stored in the storage unit.